If you had a cup (literally, 250 ml, not what some people call cups, which are actually more like 3 cups...) a day, I don't see too much of a problem. But as most things go in Western society, everything is in excess. And coffee (caffeine) in excess will promote cortisol production, and insulin resistance.
From personal experience, cutting out coffee has been one of the best things I could have done. I'm no longer tired throughout the day, and my energy levels have been stabilized. I can't justify the consumption of a stimulant, when I can't see the need for one.